Project Summary Alcohol use disorders and social anxiety disorder are highly comorbid and associated with significant impairment. Social anxiety comorbidity is associated with poorer addiction treatment engagement and outcomes. Thus, addressing underlying social anxiety symptoms that may lead to and maintain alcohol problems, as well as undermine successful treatment for alcohol use disorders, is warranted. This proposal aims to develop and evaluate a fully integrated outpatient program for comorbid social anxiety and alcohol use disorders that weaves evidence-based treatment for social anxiety disorder (i.e., exposure-based cognitive behavioral therapy) into a traditional, evidence-based treatment for alcohol use disorders. First, we will develop the protocol for the fully integrated treatment (FIT). The overarching goal of FIT will be to simultaneously deliver alcohol use disorder treatment and social anxiety disorder treatment. Development will be an iterative process guided by previous research (including our own), and by input from clinicians, administrators, and patients in an outpatient substance use disorder treatment clinic. After the protocol is developed, we will use our established clinician training procedures to train clinicians at our community partnered clinic to competently deliver the intervention. After protocol development and clinician training, we will conduct a pilot randomized clinical trial (RCT) comparing the efficacy of our fully integrated treatment (FIT) for comorbid alcohol use and social anxiety disorders to usual care (UC) in the community substance use disorder specialty clinic. The goals of the RCT will be to gather data regarding acceptability, feasibility, and preliminary efficacy of the FIT protocol. We will randomize treatment-seeking participants (N = 60) who have comorbid social anxiety and alcohol use disorders. We will assess treatment engagement, social anxiety outcomes, and alcohol use outcomes at baseline, 3-months, and 6-months from baseline. We will also gather qualitative and quantitative acceptability data from patients after completing FIT, which may guide final refinements of FIT prior to testing in a larger-scale grant. The knowledge gained from this investigation has the potential to significantly improve the treatment of alcohol use disorders and make a significant public health impact. The focus on direct translation to community practice paradigms and the emphasis on full mental health and addiction treatment integration significantly advance the field.